Pregnant Kelly Rutherford Puts Parenting First

She may be going through a nasty divorce with estranged husband Daniel Giersch, but pregnant Gossip Girl star Kelly Rutherford is staying positive and focusing on being parent.

"I'm doing great," the actress told PEOPLE Tuesday at the Lyn Devon trunk show at ARCADE by Rochelle Gores.

Asked about how she remains upbeat despite the struggles in her personal life, she says, "I'm doing so well because I know I'm making the right decision. I love my son so much and he's loved by both us – his father and I – greatly. My greatest joy in life right now is being a mom."

In January, a Los Angeles court sided with Rutherford, allowing the star to take son, Hermes, 2, to New York, where her show is filmed, until the end of March. Giersch had strongly objected, saying his home in L.A. would offer a more stable environment. Still, Giersch said that he and Kelly would work together to create a stable life for their son.

Preparing for Baby No. 2

Rutherford has been making the most of being able to split her time on both coasts with her son. "I get the best of both worlds. I get a little New York, I get a little Los Angeles and so does my son, which is fantastic. As long as there's a lot of love there, you can get through very tough times."

Set to give birth to a baby girl in June, the 40-year-old star is already prepping Hermes for his role as big brother. "I talked about him being a big brother and what that's going to mean and he gets excited about it," she says. "He loves it, he rubs my belly, he talks to the belly, it's sweet.

And while she hasn't experienced any crazy cravings, Rutherford finds herself missing a few things – like margaritas! "I can't wait to have a margarita at some point, chips and a margarita, [and] sushi," she tells PEOPLE.